Abstract: Based on the new development philosophy, this study constructs a comprehensive evaluation indicator system covering five dimensions of innovation, coordination, green development, openness, and shared prosperity. Taking the 22 districts, county-level cities, and counties of Ningxia Hui Autonomous Region as research samples, four analytical methods are employed for empirical analysis: firstly,the entropy-weighted technique for order preference by similarity to an ideal solution (TOPSIS) method is applied to measure the comprehensive level of county-level high-quality development and classify counties into different development tiers; secondly the Theil index decomposition approach is applied to quantify regional disparities and identify their structural sources; thirdly,spatial autocorrelation analysis is applied to examine the spatial dependence and agglomeration patterns of county-level high-quality development; and fourthly,a partial least squares regression (PLSR) model is applied to identify the key influencing factors of county-level high-quality development. The results reveal that county-level high-quality development in Ningxia exhibits a ladder-like differentiation pattern, with regional disparities mainly originating from inter-prefectural differences. Spatially, a three-tier pattern is observed, characterized by hotspot agglomeration in northern Ningxia, transitional development in central Ningxia, and random distribution in southern Ningxia. Furthermore, the influencing factors exhibit a hierarchical structure.